Modular structure for restraining walls



P 2, 196.9 M. A. AJNDRESEN 3,464,211

MODULAR STRUCTURE FOR RESTRAINING WALLS Filed March 8, 1967 2 Sheets-Sheet 1 FIG. I FIG. 2

INVENTOR. MAGNE A. ANDRESEN ATTORNEY p 2, 1969\ M. A. ANDRESEN 3,

MODULAR STRUCTURE FOR RESTRAINING WALLS Filed March 8, 1967 2 Sheets-Sheet 2 4Oa n 44 INVENTOR. MAGNE A. ANDRESEN ATTORNEY United States Patent Oifice 3,464,211 Patented Sept. 2, 1969 3,464,211 MODULAR STRUCTURE FOR RESTRAINING WALLS Magne A. Andresen, 3314 Putty Hill Road,

' Baltimore, Md. 21234 Filed Mar. 8, 1967, Ser. No. 621,568 Int. Cl. E04b 1/04; E04c 1/10, N30

US. C]. 61-35 4 Claims ABSTRACT OF THE DISCLOSURE A modular reinforced concrete restraining wall formed of precast rectangular parallelepiped front panels and T-shaped headers. The wall is erected without mortar and is held in position by keystone shaped male keys on each header which fit within corresponding keyway notches formed within the front panel blocks. Reinforcing bar eyelets embedded within the tops of the front panels key with slots in the bottom of abutting panels to provide added shear load resistance as well as handling means.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to earth engineering and more particularly to stable retaining structures for restraining shifting or eroding earth media.

Description of the prior art Earth restraining structures have taken a myriad of shapes and forms throughout the history of construction. The objects of their design include both the effecting of a high localized earthern shear resistance as well as the provision of a facing serving to retard erosion and improve architectural appearance.

Two design approaches for the restraint structures have continued to dominate the construction field: retaining walls, which are rigid wall structures tied intimately to a base or foundation member so as to resist overturning earth pressures; and cribbing structures, which, generally described, comprise an interlocked, box-shaped assemblage of beam-form members into which is placed an earthen fill. Thusly filled, the crib structure presents a heavy, confined earthen mass highly resistant to overturn and like forces.

Concepts have heretofore been presented to the construction industry for prefabricated retaining structures, particularly with regard to cribbing assemblies. Such assemblies suggest the immediate advantage of recovering a portion of initial restraint structure investment following unaccountable failures due to slides and the like inasmuch as the modular components are often re-usable. The use of prefabricated assemblies, however, has not been particularly extensive in view of their marginal economies and somewhat unattractive frontal appearance. As a result, poured in place, reinforced concrete retaining wall structures are often given preference for earth restrainin g functions by design engineers.

such problems are compounded by both the scarcity and cost of skilled construction labor, the economies of the modular, prefabricated earth restraint system Wane,

Several prefabricated designs for cribbing are characterized in having a series of carefully notched and interlocking generally beam shaped modules which, when assembled, form a box-shaped assembly. The disadvantages inherent in this type of structure include (a) the difficulty of introducing an adequately compressed earth backfill within the partially constructed assembly without disrupting the interlock at module junctions; (b) should a slight misalignment of the interlocking structure occur during fabrication, the error will tend to compound itself tOihfi. point of introducing unsightly aberrations in the vertical front wall facial alignment; and (c) a slight,

. spurious earth movement as might be caused by tempera- The economies which might otherwise be attached to p v ture or moisture cycling at one point in the restraining wall during or after construction will tend to chain react and disrupt the alignment of the remainder of the wall. Of course, the necessity for maintaining very careful alignment of the modules during wall fabrication imposes the expense contributing requirement of using a skilled and reliable labor force. Additionally, in all such modular structures a careful quality control must be interposed during prefabrimtion in order to assure a proper interfitting of components. Particularly Where notched concrete modules are concerned, the dimension of complex shapes are often difficult to maintain from batch to batch.

SUMMARY OF THE INVENTION The inventive modular restraining wall now presented oifers solution to the deficiencies outlined above and others by providing, inter alia, a modular Wall structure having a front or facing assembly formed of relatively large rectangular precast concrete panels which are aesthetically pleasing.

The modular restraining wall assembly is particularly characterized by its dove-keyed face wall interconnective arrangement utilizing independently suspended headers to afford the earth mass isolating advantages of a cribbing formation along with a more pleasing appearance. The dove-keyed headers of the invention are of a simply fabricated T-shape and along with the face panels of the wall are readily shipped and handled during installation.

By virtue of the use of a readily positioned and independently suspended header formation, the restraining Wall of the invention may be erected with minimal labor skill inasmuch as inadvertent positioning errors are not prone to chain react and progress throughout the wall structure. In the same light, the face panels of the instant restraining wall are readily maintained in vertical alignment during erection using only basic and relatively inexperienced labor talent.

The inventive modular wall assembly is further characterized by the utilization of only two basic structural member designs, thereby lending itself to more economically feasible module manufacturing methods and erection labor force training.

The T -shaped header formation of the instant restraining wall is designed so as to allow greater ease in providing earth backfilling during erection. An independent suspension of each of the T-shaped headers minimizes temporary delays encountered when portions of the rearward support structure are excessively jolted by earth moving or compacting machinery. The independent suspension character of the headers of the wall also tend to localize the displacements caused by unaccounted for spurious earth movements, thereby minimizing repair costs as are often encountered in cribbing wall structures and the like.

The simplicity of the restraining wall design lends it to use with a wider variety of applications and the minimization of the need for skilled erecting labor further broadens the scope of its applicability to use by constructors not having the resources to maintain a skilled labor pool.

The design now presented also offers an economic advantage in allowing for design load options. Should there exist only a possibility of later higher overburdens, the restraining wall may be simply modified at a later date at relatively minor expense to accommodate the higher earth loadings.

Other objects and advantages of the invention will be apparent from the following detailed description taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a front elevational view of a modular wall panel according to the present invention, showing in dotted fashion the placement of reinforcement.

FIGURE 2 is a sectional view taken along the line 2-2 in FIGURE 1.

FIGURE 3 is a plan view of a T-shaped header according to the invention also showing the positioning of reinforcing bars.

FIGURE 4 is a sectional view taken along the line 4-4 of FIGURE 3.

FIGURE 5 is a perspective view showing an interlock between a face panel and header of the present invention.

FIGURE 6 is a partially exploded perspective view of a restraining wall according to the instant invention.

FIGURE 7 is a side elevational view showing in cutaway fashion and erected restraining wall according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Structure Each of the front wall panels of the modular restraining wall structure of the invention are precast in the form of a rectangular parallelepiped as may be evidenced from the front panel shown generally at 10 in FIGURE 1. Throughout the several views of the drawings similar reference characters generally showing major components are employed to denote the same or similar parts.

The panels 10 are precast of concrete and are formed having wire mesh reinforcement 12 embedded at about the center of their depth. Precise placement of such reinforcement will vary according to both panel depth and conventional structural engineering principles for reinforced concrete design. The upper and lower faces 14 and 16 respectively, of the panel are formed having notches shaped as dove form keyways 18 and 20. These keyway notches are respectively indented within the noted surfaces at the center of the longitudinal or horizontal length of the panel and will be seen to have a depth amounting to one-half the height of the headers used with the invention. Similarly, each of the four corners of each front panel 10 are formed incorporating keying indentations 22, and 24 at the upper face 14 and indentations 26 and 28 at the lower face 16. Notches 22 to 28, while having the identical sidewall and depth geometry as central keyway notches 18 and 20, are formed to provide only a longitudinally symmetrical one half of the dove structure.

Also incorporated within the front panel 10 are U- shaped eyelets 30 and 32 formed from metal reinforcing bars. The eyelets are embedded within the panel so as to both project perpendicularly a definite distance above the upper face 14 and to be somewhat precisely spaced along the longitudinal and transverse axes of the panel. Disposed within lower face 16 andpreferably in alignment with the eyelets 30 and 32 are slots 34 and 36. The latter slots are formed having shape and dimensions within and geometrical position upon the lower face 16 so as to receive the respective eyelets of contiguous front panels. The eyelets 30 and 32 serve the necessary purpose of providing lifting and handling means during both the precast form-stripping procedures and in subsequent wall erection. When inserted within the slots 34 and 36 of contiguous panels within a wall there is assurance of the geometrical alignment integrity of the restraining wall face structure. It will be apparent also that a structural union is provided between adjacent panels alfording a degree of resistance to shearing loads.

The most convenient positioning of both the eyelets 3G and 32 and slots 34 and 36 is at one-fourth of the length of the panel from each end, inasmuch as it will be seen to be desirable to stagger horizontal rows of the front panels by one-half of a panel length in erecting a wall.

It will be understood that a variety of architectural designs may be incorporated within the outer faces of the front panels 10 and all such protruding members at the time of precasting.

Turning to FIGURES 3 and 4, the second and last basic member of the structural combination of the invention is illustrated as header or rearwardly projecting T- shaped member 40. Header 40 is prefabricated of concrete and is characterized in having an intimately connected stem section 42 which, for the most part, is relatively longer than its rearward cross-bar member 44.

The header 40 is further characterized by the keystone shaped male dove key shown generally at 46. Key 46 is formed having parallel, planar upper and lower surfaces respectively at 48 and 50 which, in turn, lie in the same parallel planes as the respective upper and lower faces of the rearward cross member 44. The side faces 52 and 54 of the key are planar, perpendicular to surfaces 48 and 50 and are formed to fit snugly within the keyway notches of the front panels 10. As is shown in the drawings, the keys 46 provide a seating surface 56 which nests against the rearward surface of front panels 10. Conventional reinforcing rods for providing resistance to tension loads are cast within the units as shown at 58. The size or amount of reinforcing inserted within the header 40 is determinable through conventional structural analysis in accordance with projected earth loadings. In the latter regard, however, it is important that careful structural design attention be paid to the reinforcement disposed at the union of the cross member 44 and stem 42. An alternate construction arrangement as later described may indicate that higher quantities of reinforcement may be necessary at the subject union.

The nesting of the male key 46 within a typical central keyway 18 is portrayed in FIGURES 5 and 6.

Erection procedure The two above-described structural components of the restraining wall are very simply assembled as depicted in FIGURE 6. A first horizontal line of front panels are vertically positioned over a previously positioned series of headers extending level and perpendicular therefrom. Earthen backfill is then positioned over the first layer of headers 40 and against the front panels 10 which are held in position at their lower surface by the keys 46 of headers 40. Backfilling continues until the level of the next layer of headers 40 is reached, whereupon the headers are positioned upon the backfill, their key portions 46 nesting within the top face keyways 18, 22 and 24. It will be apparent from the figure that the abutment of two front panels will form a set of corner keyways, notch 24 mating with notch 22 of the adjacent block, notch 28 mating with notch 26 of the adjacent block and so on.

As discussed earlier, the eyelets 30 and 32, mating with their corresponding slots, serve a useful function of assuring proper panel and keyway alignment during the construction phase, thereby minimizing the degree of labor skill required. Where it becomes desirable to provide a clean cut side terminus of the entire restraining wall, a panel 10 may be sawed in half or cast as a half member as shown at 10a.

FIGURE 7 provides a side elevation of a completed restraining wall according to the invention. For higher structures, it may be desirable to provide a simple footing as at 11 into which the first layer of headers 40 are positioned. FIGURE 7 further shows a restraining wall using headers 40a to 402 in which the lengths of stems 42 vary in relation to wall height. Some material savings may be realized with this arrangement where long lengths of restraining wall are contemplated. The wall is shown capped at 62.

In the course of structural design, there may occur instances where the structural engineer is uncertain as to future overburdens which may be imposed upon the earth mass restrained by the wall. In such cases, the present invention provides a design contingency option. Should an overburdening condition be encountered at a future date, conventional piling, such as H pile 61, may be driven from the top surface vertically at the internal side of the header stem 42 and cross member 40 intersection (shown generally at 60 in FIGURE 6). Such procedure will provide a local earth consolidation resistant to horizontal movement near to each header cross member. The resultant effect will constitute a hybrid result of intermixing the stability of the earthen mass crib effect of the structure originally emplaced plus the restraint provided by driven piling. It may be noted that the availability of the option itself offers wider design flexibility and consequent lower costs. Of course, the sizing of all header stems 42 must be identical in the initial structure.

While the invention has been shown and described with particular reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.

I claim:

1. A restraining wall structure for constraining an earthen media comprising:

(A) a plurality of superimposed, horizontal rows of prefabricated front panel blocks;

(B) each said row including a plurality of individual front panel blocks having a rectangular parallelepiped configuration; said front panel blocks:

(1) having their lower surfaces contactable in alignment with the upper surfaces of the front panel blocks situate there below and their end surfaces abuttable in alignment against adjacent blocks within the said horizontal row,

(2) each said block having:

(a) a notch formed inwardly from each of the four corners defined at the intersections of the said end and upper and lower surfaces, said notch being configured to provide a symmetrical one-fourth portion of a keyway, thereby forming one-half of an entire keyway when abutting the respective corner of a horizontal adjacent front panel block,

(b) a notch formed inwardly from the longitudinal midpoint of each of its upper and lower surfaces and configured to provide a symmetrical one-half portion of a said keyway,

(c) at least one metal bar eyelet protruding from and spaced regularly and consistently upon the said upper surface and embedded within said block so as to provide a lifting means for said block,

(d) at least one slot formed within and spaced upon said lower surface and adapted situated and configured to receive in shear load transferring relationship the said eyelet protruding from the next adjacent front panel block upper surface; and to retain said adjacent blocks in vertical alignment.

(C) a plurality of prefabricated T-shaped headers horizontally projecting rearwardly from the front panel blocks, suspended independently in mutually noncontacting relationship within the restrained media and having vertical and horizontal dimensions substantially smaller than the corresponding vertical and horizontal dimensions of said front panel blocks, each said header comprising (1) a stern portion having a male key portion at one end and adapted to nest within and engage the said keyways and cooperate therewith so as to restrain said front panel blocks from outward movement (2) a cross-bar member intimately connected with the other said end mutually spaced from adjacent said cross-bar members in noncontacting relationship and extending equidistantly from said stem portion so as to lie horizontally and rearwardly of the front panel blocks.

2. The restraining wall structure of claim 1 in which:

(A) said front panel block upper surface has two said metal bar eyelets spaced thereon at one-fourth the length of said block respectively from each end surface thereof; and

(B) said front panel block has two said slots within its lower surface aligned to receive the said eyelets protruding from the upper surfaces of adjacent blocks.

3. The restraining wall of claim 1 in which alternate said superimposed horizontal rows of front panel blocks are laterally transposed a distance amounting to one-half the horizontal length of one said block.

4. The restraining wall of claim 3 in which the said lengths of said header stem portions vary and said headers are positioned rearwardly of said front panel blocks having stem portions diminishing in length proportionately with their respective height above the bottom of said wall.

References Cited UNITED STATES PATENTS 400,693 4/ 1889 Lawrence 61-47 751,492 2/1904 Fraser 61-47 X 1,909,539 5/1933 Huntoon 61-47 2,035,050 3/1936 Clare 61-47 2,315,441 3/1943 McDaniel 61-47 2,333,168 11/1943 Gilman 6l-47 2,351,856 6/ 1944 Henderson 52-587 2,820,349 1/ 1958 Cooper 6147 3,282,054 11/ 1966 Saginor 61-35 FOREIGN PATENTS 1,011,707 4/ 1952 France.

JACOB SHAP-IRO, Primary Examiner US. Cl. X.R. 

